[Nut-upsdev] Tripplite OMNI1000LCD Watchdog

Thomas Golding thomasg at worldradiolink.com
Tue Dec 11 21:36:11 UTC 2007

 > -----Original Message-----
> From: Arjen de Korte [mailto:nut+devel at de-korte.org] 
> Sent: Tuesday, December 11, 2007 1:44 PM
> To: Thomas Golding
> Cc: nut-upsdev at lists.alioth.debian.org
> Subject: Re: [Nut-upsdev] Tripplite OMNI1000LCD Watchdog
> Thomas Golding wrote:
> > I'm working with usbhid-ups and a Tripplite OMNI1000LCD. I 
> used a USB 
> > packet sniffer to discover something cool about the 
> watchdog feature in this unit.
> > (not sure if the other OMNI-X-LCD models work the same or not.) 
> > Basically there's a single HID variable at Report ID 0x52
> > (UPS.OutletSystem.Outlet.ffff0092) that's one byte (0-255 
> int) and it 
> > contains the Watchdog timeout value. If it's set to zero, 
> the watchdog 
> > is effectively disabled. If it's set to >0, it represents 
> the amount 
> > of time (in seconds) the UPS will count down to reboot if it looses 
> > comms with the PC. Tripplite's PowerAlert software just writes a 
> > user-assigned number to this location to enable watchdog.
> That is a highly dangerous feature. If someone accidentally 
> removes the USB plug, it would trip the watchdog.

Yes the potential for problems is high in most environments. However, when
used in a radio transmitter shack in Alaska where the closest human is 300
miles away... invaluable. :)

> > I've looked at the code for 2.2.0, 2.2.1-pre, and SVN rev. 1170 
> > (12-08-2007) and none of them seems to implement watchdog 
> in usbhid-ups at all.
> No, although it can be done pretty easily in the subdriver. 
> There is no need to do this in usbhid-ups (and we won't do 
> that either, see below).
> > Could anyone point me in the right direction on how to code 
> > ups.watchdog.status and reset.watchdog in usbhid-ups?
> See if what I came up with in the trunk (r1175) suits your 
> needs. The following commands control the watchdog:
> 	upsc <upsname> ups.watchdog.status (shows time left)
> 	upscmd -u <user> -p <pass>] <ups> reset.watchdog[=seconds]
> By default, the latter command will write '60' to this 
> variable if called without the optional seconds, but you can 
> override this. You'll need to hack up a script that 
> periodically calls this command to keep your watchdog happy.
> This feature is far too dangerous to include in the 
> mainstream NUT, so adding these variables to the 
> tripplite-hid subdriver is as far as I want to go.

Understood. Now that you mention it, this feature is probably implemented
TOTALLY differently on other brands of UPS, so having it in the Tripplite
subdriver makes the most sense. I'll check out the latest SVN later today
and let you know how it works. I really appreciate your quick response.
Other people on the list archives have said the NUT Developers are awesome,
but now I've seen it for myself. :)

> Best regards, Arjen

Thanks Arjen,

Thomas Golding
Information Technology Engineer
World Radio Link
208-733-3551 ext. 14
thomasg at worldradiolink.com

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